BEIJING (AP) Reigning Olympic champions Masato Uchishiba of Japan and Xian Dongmei of China defended their titles in judo's half-lightweight division at the Beijing Games on Sunday.

Xian outscored North Korea's An Kum Ae to win her second straight gold medal in the women's 52-kilogram class and bring China its first judo gold of the games.

"It's different this time because it is at home," said Xian, who had a baby girl last year.

Uchishiba, competing in the men's 66-kilogram division, exploded into Benjamin Darbelet and threw the Frenchman to the ground about a minute after their final bout began. Darbelet managed to twist enough to keep the fall from ending the match, but Uchishiba then grabbed an armlock and Darbelet had to concede.

Darbelet was still grimacing in pain as Uchishiba bowed in victory.

"I know him well," Uchishiba said. "We have gone out drinking many times. I have studied him not just in judo."

Uchishiba used an ippon throw to end his first match against Dominica's Juan Jacinto Jiminez, then outscored Iran's Arash Miresmaeili and threw Uzbekistan's Mirali Sharipov to earn his berth.

He inched past Yordanis Arencibia of Cuba, who is ranked third in the world this year, in the semis. Darbelet was much more decisive in his semifinal, getting two waza ari points on Pak Chol Min of North Korea to end it early.

"I felt slow in the morning," Darbelet said. "When I felt best was in the final."

Arencibia and Pak took the bronzes. Pak, who rarely competes internationally, dedicated his win to North Korea's leader, Kim Jong Il.

"It was he who gave us the opportunity to compete here," he said.

Like Uchishiba, China's Xian began with an ippon throw 1 minute, 21 seconds into her opening match against world No. 1-ranked Ana Carrascosa of Spain. Carrascosa had been favored to win the bout and possibly the gold.

Xian used her devastating throw to defeat Algeria's Soraya Haddad in the semifinal. Haddad went on to win the bronze, along with Japan's Misato Nakamura.

At 19 and making her Olympic debut, Nakamura was seen as one of Japan's weaker shots at a gold. She earned her semifinal slot by beating Germany's Romy Tarangul, the world No. 3, and Belgium's Ilse Heylen.

She was outclassed by An, who was on the attack throughout their match and won on points.

"It's all the same if it's not a gold medal," Nakamura said. "She had more power and I tried to go against it. I should have used it against her."

There were two upsets in the early rounds of the men's competition.

World Champion Joao Derly of Brazil won his first bout with a koka, but was then beaten by Portugal's Pedro Dias. Top-ranked Zaza Kedalashvili, the European champion, also lost in overtime in his opening bout to Hungary's Mikios Ungvari, who is ranked No. 2.